Fabrication of aluminum and its alloys



Patented Jan. 1, 1935 i A l v A UNITED STATES PATENT OFFICE FABRICATION OF ALUMINUM AND ITS ALLOYS I Raymond T. Whitzel, Massena, N. Y., assignor to Aluminum Company of America, Pittsburgh, Pa., a corporation of Pennsylvania No Drawing. Application March 30, 1932 Serial No. 602,109

3 Claims. (CI. 80-60) This invention relates primarily to the rolling at least 80 per cent before attempting to develop, of structural shapes from aluminum base alloys. in the worked metal or bloom, the form of the By the term structural shapes, I refer, where structural shape desired. not otherwise qualified, to wrought products In the preferred practice of my invention, the

5 such as are used as materials of construction, aluminum base alloy ingot should have a sound, 5

widely known in the art by such descriptive clean internal structure, preferably of a uniform terms as angles, I-beams, channels, H-beams, and refined grain size, as for geigample an ingot Ts, etc. By structural shapes I distinguish such as produced by the ingotacasting method such shapes as these from members of simple described in United States Patent'l lenlfl'lflfim,

geometric section, such as rectangles, squares, of Stay & Holzhauer, in which method the 10 octagons, and the like. molten metal in the ingot mold is caused to An important object of my invention is to prosolidify from the bottom upward in a gradually vide a process by which aluminum base alloy rising plane, the top portion being the last to structural shapes may be fabricated commersolidify. By the method of this patent a cast cially and a satisfactory product produced coningot can be produced which is readily workable sistently, to the end that excessive rejections of and which has an internal structure characterfaulty material will not burden the operation ized by substantial uniformity of composition with high cost. A further important object of and grain size.

the invention is to provide aluminum base alloy Prior to working the ingot it is given a therstructural shapes which are characterized, inter mal treatment to develop or impart desirable 20 aiia, y absence of directional P y D OD properties to the metal. In this treatment such ties, o t e S ap s W have longitudinal factors as temperature, quenching or cooling, tensile properties substantially the same as those aging, etc will depend (as is well understood in in the transverse direction. the aluminum alloy arts) upon the specific al- Until recently only limited means were availby i question, I'he temperature of th treat- 25 able for the production of structural shapes from m t; i usually between about 400 ,to 550 cenaluminum base alloys, and the dimensions of the trigrade, The heated ingot is then delivered'to shapes produced were considerably below what m' or blooming r 11 and at this were desired in the commercial" application of point the reduction of t t ingot, b i

the material. Structural shapes of smaller di The complete rolling operation is divided into 30 mensions were Produced by extrusion of the two stages. In thefirst the metal is passed back metal but such methods have commercial limiand f th through the blooming l d whil tations and the Products made were for some maintaining a simple geometric shape the cross 'uses not wholly satisfactory. With the advent section of the original ingot gradually reof the use of large ingots and blooms in the rollduced In the second tage t n d tal, a mg of structural shapes of aluminum base alloy yet in simple geometric cross section, is delivered certain unforeseen difficulties developed, among to the forming mus, where for t first t them being a large number of finished Shapes the metal is worked to the structural shape which could not be used because of serious desired. Whereas the rolls used in the first or 40 feets therein. For instance, in rolling channels breakdown Stage have contours designed t from large aluminum alloy, blooms frequent duce planar surfaces, the rolls usedin the seccracking or failure of the piece occurred, thus or forming stage have varying contour the causing the rejection of sulmantial portion of indentations or projections of one forming roll the output. of the channel being so related to the contours of the other I have dlscovered that such dlmcultles were m that the metal is restricted in all directions exififofi 25m: 1512 133223 iii g i t fii 11%??? the i f must necessarily that is, insufiicient reduction of cross section 9 Festncted hmltatmn of roll sign. It is 1n the first stage of the rolling procprior to the forming of the metal into shapes v more complex than the Simple geometric form ess and prior to the second or forming stage 50 alluded to. Following this discovery I have deh in my invention a reduction of at least 150 veloped the method of the present invention, P cent of the Section thickness of e Orlglwhich in its preferred practice consists, briefly, na Cast illgOt is t0 be c v dthe reducin reducing the section thickness of the original tion is substantially less than per cent, a 55 cast ingot by forging or rolling to the extent of large portion of the metal rolled in the second or 55 forming step will fail, either by cracking, slivering, or the like, thus causing alarge number of rejections, with resulting high cost. On the other hand, I have determined that if the reduction is 80 per cent or greater, the failures in subsequent forming to the final shape are in general only such as would be expected in any metal rolling process for producing structural shapes. Moreover, by reducing the section thickness of the original ingot by at least 80 percent in the first stage, the capacityof the processis considerably increased and aluminum structural members can be fabricated of a size limited only by the size of. the ingot and the capacity of the rolling equipment.

Having thus described my invention and theof a simple geometricsection devoid of reen-' trant angles, and thereafter developing theflnal contour of the shape by forming rolls.

2. The method of making an aluminum base alloy structural shape comprising casting an ingot, reducing the cross-sectional area of the ingot at least 80 per cent in a break-down stage by subjecting the metal to the break-down action of rolls having contours designed to produce planar surfaces, and further reducing the cross-section area in a forming stage by subjecting the metal to the action of forming rolls designed to restrict the flow of the metal in all directions except the direction of rolling.

3. The method of making an aluminum base alloy structural shape comprising casting an ingot, reducing the ingot to a bloom, and thereafter developing in the worked metal of the bloom the form of the structural shape desired by subjecting the metal to the action of forming rolls, the reduction in cross-sectional area from the ingot to the bloom being at least 80 per cent. l

RAYMOND T. WHITZEL. 

